1. Field of the Invention
The present invention generally relates to an electrical plug, and in particular to a safety dual plug structure comprising primary and secondary plugs that can be selectively used.
2. Description of the Prior Art
Electrical appliances powered by built-in rechargeable cells are commonly used. The electrical appliance with built-in rechargeable cells is usually provided with a plug with/without an electrical cord for selectively connection with an electrical receptacle, such as a wall outlet of an electrical main, to charge the cells. The electrical receptacle is generally different from country to country. A conventional plug is generally designed for a receptacle of a particular country and may not be adapted in a different country. To address such a problem, adapters or chargers with a dual plug structure are available in the market and comprise two different plugs to be selectively used in compliance with the different receptacles adapted in different countries or areas.
FIG. 1 of the attached drawings shows a charging adapter 1 having a conventional dual plug structure. The adapter 1 comprises a plug 12 mounted to a first side thereof and adapted to be inserted into a cigarette lighter of a car (not shown) for receiving electricity therefrom and a recess 11 defined in an opposite second side thereof for accommodating the dual plug. The dual plug comprises a primary plug 2 received in the recess 11 and having a pair of prongs 2a, 2b. An interior space is defined in the primary plug 2 for receiving a secondary plug 3 having a pair of blades 3a, 3b movably received in slots 21a, 21b defined in the primary plug 2 in communication with the interior space thereof.
Both the secondary plug 3 and the primary plug 2 are selectively movable between an extended position for engaging with a wall outlet (not shown) and a collapsed position. When the primary plug 2 is moved to the extended position thereof, the secondary plug 3 is moved therewith thereby projecting beyond the housing of the adapter. Inadvertent contact of the blades 3a, 3b by a user attempting to plug the prongs 2a, 2b into a wall outlet may occur causing electrical shock to the user.
It is thus desirable to have a dual plug structure that eliminates the problem discussed above.